Many applications in the field of analytical research and clinical testing utilize optical methods for analyzing liquid samples. Among those methods are absorbance, turbidity, fluorescence/luminescence, and optical scattering measurements. Optical laser scattering is one of the most sensitive methods, but its implementation can be very challenging, especially when analyzing biological samples in which suspended particles are relatively transparent in the medium. In this case, most of the scattering process occurs in the forward direction near the incident laser beam. To detect this forward scattering signal, high extinction of the incident beam is required.
One particle that often requires evaluation within a liquid is bacteria. The presence of bacteria is often checked with biological liquids, such as urine, amniotic, pleural, peritoneal and spinal liquids. In a common analytical method, culturing of the bacteria can be time-consuming and involve the use of bacterial-growth plates placed within incubators. Normally, laboratory results take several days to determine whether the subject liquid is infected with bacteria.
In some systems, cuvettes have been used to receive liquid samples that are then subjected to the optical measurement by transmission of an input beam through the cuvette and observation of the forward scatter signals. These devices have been used relative to the detection of bacteria within the liquid. However, the cuvettes are not conducive to mass production for commercial use. Nor do these prior art cuvettes have user friendly features that permit for ease of use by operators. Furthermore, these prior art cuvettes lack mechanisms that permit the easy flow of the liquid sample into the optical chamber through a filter.
Accordingly, there is a need for an improved cuvette that is easy to mass produce, permits easy use by the operator, and more readily delivers the liquid sample into the optical chamber through the filter.